1. Field of the Invention
The invention relates to a wall for separating the inside of a building from the outside, to a building sheath, and to a building having such a wall, as well as to a method for the construction of a building.
2. Description of the Related Art
If there is a difference in the content of water vapor or in temperature between the outside and the inside, then there is an effort to balance out this lack of equilibrium, in that a corresponding water vapor stream or heat stream occurs. In order for no damage to the building construction to occur, the wall must be designed in such a way, among other things, that no relative humidity occurs that brings about mold formation and/or the condensation of water.
In climate zones in which the water vapor stream over the course of the year always comes from the same direction, as is predominantly the case in western Europe, for example, the wall structure is configured in such a way, in order to avoid the aforementioned problems, that the moisture can leave the wall in the direction of the vapor diffusion stream more easily than it can penetrate into the wall from the direction of the vapor diffusion stream.
However, there are also climate zones in which the water vapor stream can come from both directions, i.e. from the inside and from the outside, over the course of the year. This is typically the case in those climate zones where a rainy season occurs, and thus very high humidity combined with warm temperatures prevails over an extended period of time. If it is then cooler and/or drier indoors, for example on the basis of air conditioning, then the water vapor stream is directed from the outside to the inside. During the cooler season, in contrast, the indoor spaces are generally warmer and more humid than the outdoors, so that a water vapor stream in the opposite direction occurs. Such climate conditions, with a water vapor stream in both directions, which are found in Japan, New Zealand, and other countries, for example, promote condensation and mold formation, particularly if the indoor spaces are air conditioned.
One possibility for avoiding damage to the building construction in the case of such climate conditions consists in structuring both sides of the wall to be vapor-tight, and thus to completely prevent a vapor diffusion stream through the wall. However, this configuration has the disadvantage that it is extremely susceptible to mechanical damage, and thus can easily lose its effectiveness as the result of damage to the vapor-tight planes. Often, such a configuration is therefore not used, and it is accepted that there can be problems with regard to condensation and mold formation.